[jest-worker]: bigInt serialization in jest-worker

CHANGELOG.md

@@ -9,6 +9,7 @@
 - `[jest-runtime]` Fix regression when using `jest.isolateModules` and mocks ([#11882](https://github.com/facebook/jest/pull/11882))
 - `[jest-runtime]` Include test name when importing modules after test has completed ([#11885](https://github.com/facebook/jest/pull/11885))
 - `[jest-runtime]` Error when ESM import is used after test is torn down ([#11885](https://github.com/facebook/jest/pull/11885))
+- `[jest-worker]` Add support for serializing `bigInt` objects ([#11624](https://github.com/facebook/jest/pull/11624))
 
 ### Chore & Maintenance
 

packages/jest-worker/package.json

@@ -15,10 +15,12 @@
   },
   "dependencies": {
     "@types/node": "*",
+    "json-bigint": "^1.0.0",
     "merge-stream": "^2.0.0",
     "supports-color": "^8.0.0"
   },
   "devDependencies": {
+    "@types/json-bigint": "^1.0.1",
     "@types/merge-stream": "^1.1.2",
     "@types/supports-color": "^8.1.0",
     "get-stream": "^6.0.0",

packages/jest-worker/src/__tests__/index.test.js

@@ -14,7 +14,7 @@ let Queue;
 beforeEach(() => {
   jest.mock('../Farm', () => {
     const fakeClass = jest.fn(() => ({
-      doWork: jest.fn().mockResolvedValue(42),
+      doWork: jest.fn().mockResolvedValue({bigIntValue: 2n, value: 42}),
     }));
 
     return {
@@ -158,7 +158,24 @@ it('calls doWork', async () => {
 
   const promise = farm.foo('car', 'plane');
 
-  expect(await promise).toEqual(42);
+  expect(await promise).toEqual({bigIntValue: 2n, value: 42});
+});
+
+it('checks if bigInt type is preserved', async () => {
+  const farm = new Farm('/tmp/baz.js', {
+    exposedMethods: ['foo', 'bar'],
+    numWorkers: 1,
+  });
+
+  const promise = farm.foo('car', 'plane');
+
+  expect(await promise).toEqual(
+    expect.objectContaining({
+      /* global BigInt */
+      bigIntValue: expect.any(BigInt),
+      value: expect.any(Number),
+    }),
+  );
 });
 
 it('calls getStderr and getStdout from worker', async () => {

packages/jest-worker/src/index.ts

@@ -8,6 +8,7 @@
 /* eslint-disable local/ban-types-eventually */
 
 import {cpus} from 'os';
+import * as JSONbig from 'json-bigint';
 import Farm from './Farm';
 import WorkerPool from './WorkerPool';
 import type {
@@ -45,6 +46,10 @@ function getExposedMethods(
   return exposedMethods;
 }
 
+export function serializerWithBigInt(data: unknown): unknown {
+  return JSONbig.parse(JSONbig.stringify(data));
+}
+
 /**
  * The Jest farm (publicly called "Worker") is a class that allows you to queue
  * methods across multiple child processes, in order to parallelize work. This

packages/jest-worker/src/workers/messageParent.ts

@@ -5,6 +5,7 @@
  * LICENSE file in the root directory of this source tree.
  */
 
+import {serializerWithBigInt} from '../index';
 import {PARENT_MESSAGE_CUSTOM} from '../types';
 
 const isWorkerThread: boolean = (() => {
@@ -29,7 +30,7 @@ export default function messageParent(
     // ! is safe due to `null` check in `isWorkerThread`
     parentPort!.postMessage([PARENT_MESSAGE_CUSTOM, message]);
   } else if (typeof parentProcess.send === 'function') {
-    parentProcess.send([PARENT_MESSAGE_CUSTOM, message]);
+    parentProcess.send([PARENT_MESSAGE_CUSTOM, serializerWithBigInt(message)]);
   } else {
     throw new Error('"messageParent" can only be used inside a worker');
   }

packages/jest-worker/src/workers/processChild.ts

@@ -5,6 +5,7 @@
  * LICENSE file in the root directory of this source tree.
  */
 
+import {serializerWithBigInt} from '..';
 import {
   CHILD_MESSAGE_CALL,
   CHILD_MESSAGE_END,
@@ -64,7 +65,7 @@ function reportSuccess(result: unknown) {
     throw new Error('Child can only be used on a forked process');
   }
 
-  process.send([PARENT_MESSAGE_OK, result]);
+  process.send([PARENT_MESSAGE_OK, serializerWithBigInt(result)]);
 }
 
 function reportClientError(error: Error) {

yarn.lock

@@ -4648,6 +4648,13 @@ __metadata:
   languageName: node
   linkType: hard
 
+"@types/json-bigint@npm:^1.0.1":
+  version: 1.0.1
+  resolution: "@types/json-bigint@npm:1.0.1"
+  checksum: 374924d3a3c8620a282c8145751ef60d9daa7b627a0991e88f6a955f7d477853d2fdb9781ac125fa0bf8d2a0cc5edc1e063dcff5619332b9eb94661e0e7196f2
+  languageName: node
+  linkType: hard
+
 "@types/json-schema@npm:*, @types/json-schema@npm:^7.0.5, @types/json-schema@npm:^7.0.7, @types/json-schema@npm:^7.0.8":
   version: 7.0.9
   resolution: "@types/json-schema@npm:7.0.9"
@@ -6414,6 +6421,13 @@ __metadata:
   languageName: node
   linkType: hard
 
+"bignumber.js@npm:^9.0.0":
+  version: 9.0.1
+  resolution: "bignumber.js@npm:9.0.1"
+  checksum: 605e9639c413f344c37b23e919254f60a5017cc5ccd925e2f8fb79b36aa3d54f356df9c726f38465263236455f685d60dcf38dbe32cb0b7e4d2a32c94b035476
+  languageName: node
+  linkType: hard
+
 "binary-extensions@npm:^1.0.0":
   version: 1.13.1
   resolution: "binary-extensions@npm:1.13.1"
@@ -13313,11 +13327,13 @@ fsevents@^1.2.7:
   version: 0.0.0-use.local
   resolution: "jest-worker@workspace:packages/jest-worker"
   dependencies:
+    "@types/json-bigint": ^1.0.1
     "@types/merge-stream": ^1.1.2
     "@types/node": "*"
     "@types/supports-color": ^8.1.0
     get-stream: ^6.0.0
     jest-leak-detector: ^27.2.0
+    json-bigint: ^1.0.0
     merge-stream: ^2.0.0
     supports-color: ^8.0.0
     worker-farm: ^1.6.0
@@ -13535,6 +13551,15 @@ fsevents@^1.2.7:
   languageName: node
   linkType: hard
 
+"json-bigint@npm:^1.0.0":
+  version: 1.0.0
+  resolution: "json-bigint@npm:1.0.0"
+  dependencies:
+    bignumber.js: ^9.0.0
+  checksum: f6c550e09f25416d07d888db88e3cec6c13443b4c0ed5a903dc39b9870fc5adc77aecc30a2d4373888abce7526410a42b0bcf926382a399a285686163a479801
+  languageName: node
+  linkType: hard
+
 "json-buffer@npm:3.0.0":
   version: 3.0.0
   resolution: "json-buffer@npm:3.0.0"